Multiple arc lamp.



W. MATHIESEN.

MULTIPLE ARC LAMP. APPLICATION FILED OOT. 31 1906.

Patented May 4, 1909.

UNITED STATES PATENT OFFICE.

WILHELM MATHIESEN, OF LEUTZSGH-LEIPZIG, GERMANY.

MULTIPLE ARC LAMP.

To all whom it may concern:

Be it known that I, WILHELM MATnrEsEN, a subject of the German Emperor, residing at Leutzscl1Leipzig, in the Kingdom of Saxony and German Empire, have invented certain new and useful Improvements in Multiple- Arc Lamps, of which the following is a specification.

It is well known in connection with electric arc lamps that when a pair of electrodes have been in use the striking of the arc when the circuit is remade does not always take place with certainty unless suitable means are provided for removing from the contact-surfaces of the electrodes the non-conductive coating deposited thereon, or unless the formation of such coating is entirely prevented. In an arc lamp in which two or more pairs of simultaneously inserted electrodes are used in succession, it is, in the absence of special means for improving contact, very difficult to strike an are between electrodes which have been exposed to the products of combustion emanating from the are 01' arcs previously used. The means used to facilitate the striking of the arc in ordinary arc lamps are insufficient in the case of multiple carbon arc lamps unless combined with auxiliary devices for improving the contact made.

The purpose of the present invention is to provide means for preventing the formation of non-conductive deposits on electrodes in multiple carbon arc lamps.

In the drawings,Figure 1, which is a section on the line 11 of Fig. 2, shows the best way now known to me of carrying out my in vention. Fig. 2 is a plan of the devices illustrated in Fig. 1.

As shown, there are two sets of converging carbons or electrodes mounted to slide in guides or sockets g, g. The electrodes instead of being tapered or rounded at their lower ends as usual are squared off, i. a, the end of each electrode as shown is made flat and circular in cross section and this flat surface lies in a plane at right angles to the major aXis of the electrode. In this way the initial arc-forming portion of the electrode is protected in the manner presently described.

Specification of Letters Patent.

Application filed. October 31, 1906.

Patented May 4, 1909.

Serial No. 341,413.

1 Of course the end of the electrode need not be shaped precisely in the manner described but it should be so shaped that the initial arcforming portion thereof shall lie close to the walls of the guide or socket in which it is arranged which guide thus covers the initial arc-forming portion of the electrode and pre vents deposit thereon. While the carbons or electrodes 0, e are in use, the carbonsf, f are withdrawn into the guides, in the manner illustrated in Fig. 1. When the arc is first struck, it will be formed at the parts marked a of the electrodes, these being what I call the initial arc-forming portions of the electrodes. When the electrodes have their lower ends raised into the guides or sockets, as illustrated atj; f, Fig. 1, the initial arc-forming portionsof the electrodes are fully protected, being in close contact with the sides of the guides and no deposits can be made on the parts, at. Any deposits made on the end portions of the electrodes will not interfere with the formation of the are when the reserve electrodes are lowered. The arcs struck by the two pairs of electrodes are in the same plane or at the same level and when the are is formed by the first set of electrodes, the reserve set is elevated above the lower ends of the first set, therefore no shadow is cast and the arrangement shown is such that either set of carbons may be used first.

I claim:

A multiple carbon are lamp having a pair of converging electrodes with squared off ends, guides for said electrodes, a pair of converging electrodes with squared off ends and guides in which the said reserve electrodes snugly fit with the initial arc-forming portions thereof in close contact with the walls of the guides whereby said initial arc-forming portions are protected from the fumes emanating from the arcs struck between the electrodes in use.

The foregoing specification signed at Leipzig, this 15th day of October, 1906.

WILI-IELM MATIIIESEN.

In presence of- PAUL HEYCK, RUDOLPH FRIGKE. 

